title: Effect of monovalent cations on the aggregation of tobacco mosaic virus by chondroitin sulfate.
abstract: The mechanism of precipitation of tobacco mosaic virus by chondroitin sulfate in the presence of various monovalent cations was investigated kinetically by means of turbidimetry. The virus solution became turbid on the addition of chondroitin sulfate, and led to separation of the virus as a crystalline phase. In the presence of monovalent cations the degree of precipitation of the virus by chondroitin was reduced with the increase in monovalent cation concentration. The order of the reduction was Li+ less than Na+ less than K+, which is reversely analogous to the lyotropic series. The least hydrated cation, K+, reduced the degree of precipitation of tobacco mosaic virus the most because the radius of the sphere equivalent to chondroitin sulfate was diminished most strongly by K+ ion. The effect of the monovalent cations on the precipitation supports our assumption that the virus precipitation results from incompatibility and mutual spatial exclusion between the virus and chondroitin. The maximum turbidities, the initial slopes, and the aggregation half-time were measured by varying the monovalent cation concentrations. The former two parameters decreased with the increase in cation concentration, whereas the aggregation half-time increased. A lag time was present and the effect of the cations increased in the order K+ less than Na+ less than Li+.
mesh_terms: D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002621:Chemistry; D002807:Chondroitin / Q000031:analogs & derivatives*; D002809:Chondroitin Sulfates / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008094:Lithium / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology*; D012964:Sodium / Q000494:pharmacology*; D014027:Tobacco Mosaic Virus / Q000187:drug effects*
chemical_list: D002807:Chondroitin; D002809:Chondroitin Sulfates; D008094:Lithium; D012964:Sodium; D011188:Potassium